柔性高分子／液晶共混体系的相分离初期动力学

由Ｆｌｏｒｙ－Ｈｕｇｇｉｎｓ的柔性高分子溶液的格子模型和Ｌｅｂｗｏｈｌ－Ｌａｓｈｅｒ液晶模型结合起来导出的高分子／液晶复合体系的混合自由能泛函，并引入ＴＤＧＬ方程以用描述体系的相分离动力学。线性化理论的计算结果表明，高分子／液晶复合体系的相分离初期行为与描述普通两元熔体的相分离初期的Ｃａｈｎ－Ｈｉｌｌｉａｒｄ理论结果十分相似，即Ｓｐｉｎｏｄａｌ区域内，浓度涨落随时间变化呈指数式增长，面散射函数的峰

Early stage phase separation kinetics in flexible polymer/liquid crystal mixture

In this paper, Lebwohl-Lasher model of nematogens and Flory-Huggins latticemodel of polymers have been combined to derive the free energy function of polymer/liquidcrystal mixture. By incorporating this free energy into TDGL equation,the kinetics of phaseseparaTion in polymer/liquid crystal mixture is described. The result of linear theory showsthat the phase separation behavior of polymer/liquid crystal mixture at early stage is similarto that o conventional binary melts,which have been treated by Cahn-Hilliard theory,that is,in spinodal regime, the concentration fluctuation (i. e. light scattering intensity) grows up exponentially with time but the position of the maximum of scattering function,qm,doeos notchange with time. Besides,the polymer/liquid crystal mixture has two spinodal regime,i. e.,nematic spinodal regime and isotropic spinodal regime. Moreover,because the liquid crystal innematic state repels flexible polymer strongly,so that the speed of early stage phase separation in nematic spinodal regime will be accelerated and the scattering intensity will also bemuch stronger than that in isotropic spinodal regime.